This invention relates to a Ziegler type carrier catalytic component for .alpha.-olefin polymerization or copolymerization which is of highly uniform particle diameter, of good fluidity and has a long durable, high degree of polymerizing activity (hereinafter will be called the catalytic component for short unless otherwise specified) and to a method of carrying out homo- or co-polymerization (hereinafter will be called (co-) polymerization) of an .alpha.-olefin in the presence of a catalytic composition consisting of the above stated catalytic component and an organo-aluminum compound.
More particularly, the invention relates to a catalytic component for .alpha.-olefin polymerization prepared through steps including (a) a step in which an organo-magnesium compound expressed by the generic formula of RMgX (wherein R represents a hydrocarbon group having 1 to 20 carbon atoms and X either a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms) is allowed to react with carbon tetrahalide in the presence of an electron donor compound to obtain a solid product, (b) a step in which the solid product is treated with phenols at 90.degree. to 180.degree. C., and (c) another step in which the phenol treated product is treated further with a halogenated titanium compound. The invention also relates to a method for (co-) polymerization of an .alpha.-olefin which is carried out in the presence of a catalyst composition consisting of the catalytic component thus obtained and an organo-aluminum compound.
It is an important feature of the present invention that the polymer product is obtainable in accordance with the invention in large weight per unit weight of the catalytic component used, that is, the catalytic component according to the present invention has a high degree of polymerizing activity. Another important feature of the invention resides in that the insufficient bulk density which has been a shortcoming of the conventional carrier catalytic components of the Ziegler type can be substantially improved by the use of the catalytic component according to the invention. In addition to these important features, it is a further important feature of the invention that the polymer obtainable in accordance with the invention is of such a large particle size that the polymer product obviates the necessity of a pelletizing process. The polymer does not includes fine particles and is of uniform particle diameter. Besides, it is an advantage of the catalytic component according to the invention that use of the catalytic component permits polymerization of propylene at a high temperature which has hitherto been extremely difficult. Another advantage of the invented catalytic component resides in that the polymerizing activity of the catalytic component is highly durable.
Generally, the catalysts which have been used for the manufacture of .alpha.-olefin polymers are of the type known by the name of a Ziegler-Natta catalyst consisting of a transition metal belonging to the groups IV-VI of the periodic table and an organo-metallic compound of a metal belonging to the groups I-III of the periodic table.
Recently, there have been proposed some supported catalytic components using a halogenated magnesium compound as carrier and having a transition metal supported on the surface of the carrier. In most of these catalytic components, magnesium chloride or magnesium chloride which has undergone some surface treatment is employed as carrier and is arranged to support titanium tetrachloride on the surface thereof. Most of them thus belong to the Ziegler type. However, the catalytic component preparing method using magnesium chloride as starting material for a carrier necessitates a pulverization process for activation as well as pulverization of the magnesium chloride. Then, the pulverization process gives powdery magnesium chloride in a crushed state not only lacking uniformity of particle diameter but also containing a large amount of fine powder. This results in lack of uniformity of particle diameter of not only the catalytic component obtained by the use of the magnesium chloride but also a polymer obtained from the use of the catalytic component. The polymers that have been obtained from the use of such a catalytic component have been extremely inferior in morphology such as fluidity, etc. A polymer of such inferior morphology produces powdery dust during molding and working processes to lower the efficiency of such processes. To solve this problem, therefore, it has been a general practice to pelletize such polymers before use of them.
An .alpha.-olefin product that permits omission of the pelletizing process would permit reduction in size of an .alpha.-olefin polymer manufacturing plant, reduction in the cost of construction of the plant and further reduction in energy consumption required after the manufacture of the .alpha.-olefin polymer and before shipment thereof to the market. These merits then result in substantial reduction in the manufacturing cost of the .alpha.-olefin polymer product.
Meanwhile, many catalytic components of improved morphology also have recently been proposed. Typical examples of these proposals include: Japanese Patent Application Laid-Open No. 54-41985 which discloses a method wherein an oxygen containing magnesium compound is granulated into spherical particles, with the particle diameter of them then adjusted through a sieving process; after sieving, treatments are carried out with a transition metal compound, an electron donor compound and an organo-metallic compound one after another; and then the treated matter is again treated with a transition metal compound. Also included is Japanese Patent Application Laid-Open No. 55-58207 which discloses a method wherein a solid product obtained by allowing an organo-magnesium compound and silicon tetrachloride to react with each other is treated with alcohols and carboxylic acid esters and, after that, the treated matter is treated further with titanium tetrachloride.
However, catalytic components obtained in accordance with these prior art methods either have a low degree of durability of polymerizing activity with initial high polymerizing activity rapidly decreasing after the initial stage of polymerization or give a polymer product of insufficient bulk density. These shortcomings of the catalytic components of the prior art seem to have been preventing them from becoming acceptable for practical applications.
Another shortcoming of the prior art catalytic components of the Ziegler type resides in their insufficient polymerizing properties at high temperature. The higher the polymerizing activity of the catalytic component is, the greater the momentary calorific value will be in such a case. Therefore, it is almost impossible to prevent local over-heating, even if the temperature control over the whole inside of a reactor is possible. Therefore, a catalytic component of high polymerizing activity is required to be also capable of retaining its performance even when an .alpha.-olefin polymerization process is carried out at a high temperature.
Meanwhile, in an attempt to eliminate the above stated shortcomings of the prior art catalytic components of the Ziegler type which are arranged to support titanium, the present inventors have strenously conducted studies and have come to complete the present invention.